(a) Technical Field
The present invention relates to a route searching method of a navigation system. More particularly, the present invention relates to a route searching method of a navigation system, which provides a safer route by avoiding a dangerous route.
(b) Background Art
A navigation system is a system that displays a current position of a moving object, such as a vehicle, on a screen (e.g., a display screen), using information received from a global positioning system (GPS). The navigation system is incorporated in a variety of moving objects such as vessels, aircraft and vehicles to identify the current position and moving speed of a moving object or determine a movement route of the moving object.
For navigation systems applied to a vehicle driving on a road, the navigation system visually and audibly provides various types of information such as a current driving road and a current position. In addition, the navigation system provides a driver with various types of information used for driving by displaying an advancing direction of the vehicle, a distance to a desired destination, a current moving speed, a route set by the driver before driving the vehicle, a final route to the destination, and the like. However, the route searching method of the navigation system generally guides a path toward a destination by reflecting the shortest path.
FIG. 1 is an exemplary view illustrating a route searching method of a conventional navigation system. When a driver selects an arrival point as a destination in the conventional navigation system within a vehicle, the conventional navigation system guides a route as shown in arrow of FIG. 1. That is, the conventional navigation system guides a route using a shortest route. However, the route generates a situation in which the vehicle may have to cross a five-lane road through a short route to move from a start point to the destination. When the vehicle moves across a substantial number of lanes at a time, the risk of a car accident may increase. Therefore, to reduce the risk of a car accident, the driver should be guided to another route that avoids the dangerous path when the shortest path is determined to be unsafe.
FIG. 2 is an exemplary view illustrating the route searching method of the conventional navigation system, which briefly represents the situation of FIG. 1, using nodes. The conventional navigation system considers only whether first to third nodes are sequentially connected in the movement of the first to third nodes, and does not decide whether the drive from the second node to the third node is possible. However, whether the drive from the second node to the third node is dangerous and whether the drive from the second node to the third node is possible are actually determined by whether the vehicle drives to the first node in direction A or B. In other words, when the vehicle is driven to the first node in the A direction, the movement from the second node to the third node is determined to be safe. However, when the vehicle is driven to the first node in the B direction, the movement from the second node to the third node is determined to be dangerous (e.g., unsafe) since the vehicle must immediately turn right and left. The conventional navigation system simply connects links between nodes on a shortest route. Accordingly, the conventional navigation system does not avoid a route having a high risk of an accident despite the route being a shortest route.